Amazon has released an SDK that you can use to call Amazon Web Services from your node.js apps.
As the blog post describing the new SDK says:
Node.js provides an event-driven non-blocking I/O model to allow your applications to scale while keeping you from having to deal with threads, polling, timeouts, and event loops. You can, for example, initiate and manage parallel calls to several Web services in a clean and obvious fashion.
The preview SDK is available as an npm (Node Packaged Module) and Amazon is looking for comments on how it can be improved.